Hey there, so my wife was just feeding our fish this afternoon and came across this as she was just looking at the tank. Not sure what it is and thats why i came on here hoping to get an answer. It is only on one of the live rocks. The rock is about 4 inches in size. The white fluffy looking tubes as you can see cover about an 1/8 of the rock. Please let me know good/bad/or just ugly lol. Thanks for any and all input.